​Both Firefox and Internet Explorer have the ability to spell check text that you enter on web sites you are using. This is particularly handy when you are typing out information in an online e-mail web site, or using a tool like this social.MRSware site.

In Firefox, starting with version 2.0 spell checking is built in and enabled by default. Type something incorrectly and watch the red line appear underneath it. In some cases, you might have to right-click in the text field and choose "Spell check this field" from the menu.